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The title hydrated molecular salt, C19H15N4+ ·Cl ·2.5H2O, has two triphenyltetrazolium cations, two chloride anions and five water molecules in the asymmetric unit. The cations differ in the conformations of the phenyl rings with respect to the heterocyclic core, most notably for the C-bonded phenyl ring, for which the N—C—C—C torsion angles differ by 36.4 (3)°. This is likely a result of one cation accepting an O—H...N hydrogen bond from a water molecule [O...N = 3.1605 (15) A˚ ], while the other cation accepts no hydrogen bonds. In the extended structure, the water molecules are involved in centrosymmetric (H2O)2Cl2 rings as well as (H2O)4 chains. An unusual O—H...&#960 interaction and weak C—H...O and C—H...Cl hydrogen bonds are also observed. [ABSTRACT FROM AUTHOR]

The synthesis of a nanocomposite material consisting of Cu nanoparticles encapsulated in halloysite nanotubes (Cu@Hal) was achieved by the reduction of Cu(NO3)2 ⋅ 3H2O with sodium ascorbate/sodium borohydride in an aqueous suspension of trisodium citrate and halloysite. The nanocomposite was found to be an effective heterogeneous catalyst for the multicomponent copper catalyzed azide‐alkyne cycloaddition reaction (CuAAC). A variety of terminal alkynes reacted with benzyl halides and sodium azide in the presence of Cu@Hal in water. In situ formation of the organic azides afforded the corresponding 1,4‐disubstituted 1,2,3‐triazoles regioselectivily, in excellent yields. The catalyst was easily recovered and recycled without loss of activity with low metal leaching. [ABSTRACT FROM AUTHOR]

The effects of the ferrocenyl moiety to enhance the nucleophilicity of the carbonyl group, situated at its adjacent position, have been explored in a series of α-ferrocenyl ketocarboxylic acids. In the presence of trifluoroacetic anhydride, 3-ferrocenoylpropionic acid and 4-ferrocenoylbutyric acid gave 5-ferrocenyl-4-trifluoroacetyl-2(3H)-furanone and 6-ferrocenyl-5-trifluoroacetyl-3,4-dihydropyran-2-one, respectively. Under similar reaction conditions, 2-ferrocenylcarbonylbenzoic acid, a keto carboxylic acid without a β-hydrogen, gave a dimerized lactone, 3,3′-diferrocenyl-3,3′-diphthalide, possibly due to radical coupling. The nucleophilic attack of carbonyl oxygen, activated by the ferrocenyl moiety, on the carboxylic carbon is assumed to be the crucial mechanistic step in forming these lactones. When the carbonyl group was reduced to an alcohol to break its conjugation with the ferrocenyl moiety, saturated lactones were isolated after the acidic workup. These results indicate that the α-ferrocenyl carbinols readily undergo solvolysis under acidic conditions, giving ferrocenylcarbenium ions, which are attacked by the carboxy oxygen to give lactones. [ABSTRACT FROM AUTHOR]

C50H44Cl4CoF2N2P2, orthorhombic, Pbca (no. 61), a = 18.4662(6) Å, b = 15.2888(5) Å, c = 33.2661(10) Å, V = 9391.9(5) Å3, Z = 8, Rgt(F) = 0.0403, wRref(F2) = 0.1005, T = 180.0(5) K.

The reaction between CpRu(PPh3)2NCS (1a) and PMePh2 yields CpRu(PPh3)(PMePh2)NCS (2a) while CpRu(PPh3)(PMePh2)Cl reacts with SCN− to form the S-bonded isomer, CpRu(PPh3)(PMePh2)SCN (2b). Compound 1a and the linkage isomers of 2 were characterized by X-ray crystallography. The kinetics of the reaction between 1a and PMePh2 under pseudo-first order conditions in THF and in fluorobenzene to form 2a are consistent with a dissociative interchange mechanism. Activation parameters for the reaction are: ΔH† = 15.7 ± 0.6 kcal mol−1 and ΔS† = –35 ± 2 cal mol−1 K−1 in THF vs. ΔH† = 24.8 ± 1.2 kcal mol−1 and ΔS† = –6 ± 4 cal mol−1 K−1 in C6H5F. In the presence of added SCN−, the rate of phosphine substitution is unchanged but a mixture of 2a and 2b is observed. The selenocyanate derivative, CpRu(PPh3)2SeCN (3b), crystallizes as the Se-bonded linkage isomer. Compound 3b reacts with PMePh2 under pseudo-first order conditions in fluorobenzene to form CpRu(PPh3)(PMePh2)SeCN (4b) at a much faster rate than 1a with activation parameters: ΔH† = 30.9 ± 4.8 kcal mol−1 and ΔS† = 22.4 ± 15.9 cal mol−1 K−1 with no evidence for linkage isomerization to the N-bonded products. [ABSTRACT FROM AUTHOR]